Funding for this research was provided by:
National Natural Science Foundation of China (No. 81571948)
Natural Science Foundation of Beijing Municipality (No. 7172075)
the medical research project of Chongqing Health and Family Planning Commission (No. 2016ZDX041)
Text and Data Mining valid from 2019-10-16
Received: 15 May 2019
Accepted: 24 September 2019
First Online: 16 October 2019
Compliance with ethical standards
: This study was approved by the Ethics Committee of Beijing Children’s Hospital Affiliated to Capital Medical University. Written informed consents were obtained from the patients’ legal guardian.
: The authors declare that they have no competing interests.